Here is Irving Koppel's WWII Draft Registration Card:
Also, here is the website where I found Irving Koppel in a photo for the Air Armament School. Irving is #174 in the photo: https://web.archive.org/web/20180901024401/http://goldbergcohenfamily.info/johnkhistory.html
There were two Irving Koppel's from Chicago that enlisted in WWII. The other Irving Koppel was born 1920 in Chicago, so make sure not to mix them up!
I would appreciate any additional information about the Irving Koppel who was born in 1925 in Chicago and his military records.